Object Detection Using Recurrent Neural Network And Concatenated Feature Map

ABSTRACT

According to one embodiment, a system includes a sensor component and a detection component. The sensor component is configured to obtain a first stream of sensor data and a second stream of sensor data, wherein each of the first stream and second stream comprise a plurality of sensor frames. The detection component is configured to generate a concatenated feature map based on a sensor frame of a first type and a sensor frame of a second type. The detection component is configured to detect one or more objects based on the concatenated feature map. One or more of generating and detecting comprises generating or detecting using a neural network with a recurrent connection that feeds information about features or objects from previous frames.

TECHNICAL FIELD

The disclosure relates generally to methods, systems, and apparatusesfor detecting objects or visual features and more particularly relatesto methods, systems, and apparatuses for object detection using arecurrent neural network and concatenated feature map.

BACKGROUND

Automobiles provide a significant portion of transportation forcommercial, government, and private entities. Autonomous vehicles anddriving assistance systems are currently being developed and deployed toprovide safety, reduce an amount of user input required, or eveneliminate user involvement entirely. For example, some drivingassistance systems, such as crash avoidance systems, may monitordriving, positions, and a velocity of the vehicle and other objectswhile a human is driving. When the system detects that a crash or impactis imminent the crash avoidance system may intervene and apply a brake,steer the vehicle, or perform other avoidance or safety maneuvers. Asanother example, autonomous vehicles may drive and navigate a vehiclewith little or no user input. Object detection based on sensor data isoften necessary to enable automated driving systems or drivingassistance systems to safely identify and avoid obstacles or to drivesafe.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive implementations of the presentdisclosure are described with reference to the following figures,wherein like reference numerals refer to like parts throughout thevarious views unless otherwise specified. Advantages of the presentdisclosure will become better understood with regard to the followingdescription and accompanying drawings where:

FIG. 1 is a schematic block diagram illustrating an implementation of avehicle control system that includes an automated driving/assistancesystem;

FIG. 2 is a schematic block diagram illustrating a neural network withrecurrent connections, according to one implementation;

FIG. 3 is illustrates a perspective view of a roadway as captured by avehicle camera, according to one implementation;

FIG. 4 is a schematic block diagram illustrating incorporation oftemporal information between frames of sensor data during objectdetection, according to one implementation;

FIG. 5 is a schematic flow chart diagram illustrating a method forobject detection, according to one implementation;

FIG. 6 is a schematic block diagram illustrating creation and use of aconcatenated feature map in combination with incorporation of temporalinformation between frames of sensor data during object detection,according to one implementation;

FIG. 7 is a schematic flow chart diagram illustrating another method forobject detection, according to one implementation; and

FIG. 8 is a schematic block diagram illustrating a computing system,according to one implementation.

DETAILED DESCRIPTION

For safety reasons, an intelligent or autonomous vehicle may need to beable to classify objects in dynamic surroundings. Deep convolutionalneural networks have had great success in the domain of objectrecognition, even exceeding human performance in some conditions. Deepconvolutional neural networks can be highly proficient in extractingmappings of where high level features are found within images. Thesefeature maps may be extracted from convolutions on a static image andthen be used for image or object recognition.

State of the art object detection within images/videos has focused onextracting feature maps from static images, then feeding them intoclassification and regression models for object detection/classificationand localization, respectively. Thus, while deep convolutional neuralnetworks have had great success in the domain of object recognition, thedetection of an unknown number of objects within a scene yields a muchgreater challenge. While recent innovations have attained impressiveresults for detecting objects within static images, applicants haverecognized that existing models lack the capability to leverage temporalinformation for object detection within videos, or other series orstreams of sensor data. This can result in unstable object localization,particularly when objects become temporarily occluded.

Furthermore, detecting objects in videos with undesirable lightingconditions remains highly challenging. For example, glare from the sunor dark night-time conditions can render vision-based algorithms almostuseless. Applicants have recognized that available models lack thecapability to leverage temporal dynamics combined with information fromalternative sensors at the feature level for object detection. This canresult in unstable object localization that fails in poor lightingconditions.

In the present disclosure, applicants disclose the use of concatenatedfeature maps and recurrent connections within classification andregression models (such as a neural network) when extracting featuremaps from or detecting objects in video sequences. According to oneembodiment, a system includes a sensor component and a detectioncomponent. The sensor component is configured to obtain a first streamof sensor data and a second stream of sensor data, wherein each of thefirst stream and second stream comprise a plurality of sensor frames.The detection component is configured to generate a concatenated featuremap based on a sensor frame of a first type and a sensor frame of asecond type. The detection component is configured to detect one or moreobjects based on the concatenated feature map. One or more of generatingand detecting comprises generating or detecting using a neural networkwith a recurrent connection that feeds information about features orobjects from previous frames (e.g., feature maps or object predictionsfrom the preceding frame or frames).

According to another example embodiment, a method for object detectionin videos (or other series of sensor frames) includes determining, usingone or more neural networks, an output for a first sensor frameindicating a presence of an object or feature. The method includesfeeding the output for the first sensor frame forward as an input forprocessing a second sensor frame. The method also includes determiningan output for the second sensor frame indicating a presence of an objector feature based on the output for the first sensor frame.

In one embodiment, recurrent connections are connections that enable aneural network to use outputs from the previous image frame as inputs tothe current image frame. The recurrent connections disclosed herein mayeffectively allow for neural networks to maintain state information. Forexample, if a neural network detects a car within the current imageframe, this could impact the current state of the network and make itmore likely to detect a car at that location, or nearby location, in thenext frame. Recurrent layers can be used for attending to dynamic objectlocations prior to the final object classification and localizationlayers. They could also be used during the final object classificationstage. These recurrent layers may receive inputs from feature mapsextracted from one or more layers of the convolutional network.

While feature extraction techniques may have included varying degrees oftemporal information, regression and classification models used forattending to and/or classifying objects have focused on static images,ignoring valuable temporal information. Applicant proposes a solution toutilize recurrent connections within the regression and classificationmodels that will enable the object detectors to incorporate estimates ofthe object locations/types from the previous time frames, therebyimproving the predictions. The recurrent connections can providebenefits of object tracking at a lower level and with confidence metricslearned implicitly by the neural models. In one embodiment, techniquesdisclosed herein may be used for end-to-end object detection algorithmsto be applied to such tasks as car, bicycle, and pedestrian detection.Additionally, specific image or sensor data features can be detectedusing these methods to improve feature detection. Features may includepatterns in data such as image data, depth map data, point cloud data,or other data. For example, a feature in image data may include an edge(location of high contrast) or lines with specific curvatures, patterns,or shapes that may be of interest in object detection.

The present disclosure also proposes the use of multiple streams offeature map extractions for information attained from multiple sensortypes, such as RGB maps (images) and depth maps. Recurrent connectionsmay be used during fusion of the feature maps or during objectdetection. Depth maps can be extracted from sensors such as LIDAR,radar, or cameras (such as infrared depth cameras). In the case ofsensors that return point clouds (e.g. time of flight sensors like radaror LIDAR), additional processing may be performed to transform the pointcloud into a depth map. For example, a modified bilateral filter can beused to smooth the point cloud into a depth map while preserving edges.After the depth map is registered with the RGB camera frame, the depthmap can then be additionally decomposed into features such as horizontaldisparity, height above ground, and the angle of the pixel's localsurface normal.

The depth map may be fed into a deep fully convolutional network toextract a feature map. This may be performed in parallel with thecorresponding RGB image frame. A feature map may include a map of whichfeatures are found in which locations on an image or other sensor frame.For example, a feature map may indicate regions where features that maycorrespond to pedestrians are located. The feature maps from the depthand RGB feature maps are then concatenated and further sent throughfurther convolutional layers in the network. The concatenated featuremap may include features derived from both an image (e.g., RGB image)and a depth map. For example, a feature map may include all pedestrianor other features detected based on analysis of any available sensorframes for the same time period. For example, a LIDAR point cloud andimage frame may be captured within the same time period and the featuresdetected may be combined into a single feature map.

Recurrent layers can be used for attending to dynamic object locationsprior to the final object classification and localization layers. Theycould also be used during the final object classification stage. Theserecurrent layers will receive inputs from feature maps extracted fromthe combined depth and RGB feature maps from one or more layers of theconvolutional network. This will enable spatiotemporal relations to beextracted from fusions of the color and depth streams.

While feature extraction techniques have included varying degrees oftemporal information, regression and classification models used forattending to and/or classifying objects have focused on static images,ignoring valuable temporal information. Applicant proposes a solution toutilize recurrent connections within the regression and classificationmodels that will enable the object detectors to incorporate estimates ofthe object locations/types from the previous time frames, therebyimproving the predictions. This may yield similar or improved benefitsover object tracking, but at a lower level and with confidence metricslearned implicitly by the neural models. Furthermore, the use ofconcatenated feature maps may significantly improve object detection inthe case of poor quality for one type of sensor data.

Further embodiments and examples will be discussed in relation to thefigures below.

Referring now to the figures, FIG. 1 illustrates an example vehiclecontrol system 100 that may be used to automatically detect, classify,and/or localize objects. The automated driving/assistance system 102 maybe used to automate or control operation of a vehicle or to provideassistance to a human driver. For example, the automateddriving/assistance system 102 may control one or more of braking,steering, acceleration, lights, alerts, driver notifications, radio, orany other auxiliary systems of the vehicle. In another example, theautomated driving/assistance system 102 may not be able to provide anycontrol of the driving (e.g., steering, acceleration, or braking), butmay provide notifications and alerts to assist a human driver in drivingsafely. The automated driving/assistance system 102 may use a neuralnetwork, or other model or algorithm to detect or localize objects basedon perception data gathered by one or more sensors.

The vehicle control system 100 also includes one or more sensorsystems/devices for detecting a presence of objects near or within asensor range of a parent vehicle (e.g., a vehicle that includes thevehicle control system 100). For example, the vehicle control system 100may include one or more radar systems 106, one or more LIDAR systems108, one or more camera systems 110, a global positioning system (GPS)112, and/or one or more ultrasound systems 114. The vehicle controlsystem 100 may include a data store 116 for storing relevant or usefuldata for navigation and safety such as map data, driving history orother data. The vehicle control system 100 may also include atransceiver 118 for wireless communication with a mobile or wirelessnetwork, other vehicles, infrastructure, or any other communicationsystem.

The vehicle control system 100 may include vehicle control actuators 120to control various aspects of the driving of the vehicle such aselectric motors, switches or other actuators, to control braking,acceleration, steering or the like. The vehicle control system 100 mayalso include one or more displays 122, speakers 124, or other devices sothat notifications to a human driver or passenger may be provided. Adisplay 122 may include a heads-up display, dashboard display orindicator, a display screen, or any other visual indicator which may beseen by a driver or passenger of a vehicle. The speakers 124 may includeone or more speakers of a sound system of a vehicle or may include aspeaker dedicated to driver notification.

It will be appreciated that the embodiment of FIG. 1 is given by way ofexample only. Other embodiments may include fewer or additionalcomponents without departing from the scope of the disclosure.Additionally, illustrated components may be combined or included withinother components without limitation.

In one embodiment, the automated driving/assistance system 102 isconfigured to control driving or navigation of a parent vehicle. Forexample, the automated driving/assistance system 102 may control thevehicle control actuators 120 to drive a path on a road, parking lot,driveway or other location. For example, the automateddriving/assistance system 102 may determine a path based on informationor perception data provided by any of the components 106-118. The sensorsystems/devices 106-110 and 114 may be used to obtain real-time sensordata so that the automated driving/assistance system 102 can assist adriver or drive a vehicle in real-time. The automated driving/assistancesystem 102 may implement an algorithm or use a model, such as a deepneural network, to process the sensor data to detect, identify, and/orlocalize one or more objects. In order to train or test a model oralgorithm, large amounts of sensor data and annotations of the sensordata may be needed.

The automated driving/assistance system 102 may include a detectioncomponent 104 for detecting objects, image features, or other featuresof objects within sensor data. In one embodiment, the detectioncomponent 104 generates a concatenated feature map based on multiplekinds of streaming sensor data. For example, the detection component 104may generate a feature map based on an image and a feature map based ona depth map derived from radar, LIDAR, infrared camera, or other sensordata. A concatenated feature map may be generated that includes all ofthe features from the different sensor maps. Thus, if one sensor is notproviding good data, the concatenated feature map may still have all thefeatures or object detected using data from a different sensor.

In one embodiment, the detection component 104 may use recurrentconnections in a classification or regression model for detecting objectfeatures or objects. For example, the detection component 104 mayinclude or utilize a deep convolutional neural network that outputs, viaa classification layer, an indication of whether an object or feature ispresent. This output may then be fed forward to a subsequent image orsensor frame. Feeding the output of one sensor frame to the next mayallow for benefits to similar to object tracking, but at a much lowerlevel that allows a system to benefit from the power of neural networks,such as training and machine learning.

FIG. 2 is a schematic diagram illustrating a deep neural network 200with a recurrent connection. Deep neural networks are feed-forwardcomputational graphs with input nodes (such as input nodes 202), one ormore hidden layers (such as hidden layers 204, 206, and 208) and outputnodes (such as output nodes 210). For classification of contents orinformation about an image, pixel-values of the input image are assignedto the input nodes, and then fed through the hidden layers 204, 206, 208of the network, passing through a number of non-linear transformations.At the end of the computation, the output nodes 210 yield values thatcorrespond to the class inferred by the neural network. Similaroperation may be used for classification or feature detection of pixelcloud data or depth maps, such as data received from range sensors likeLIDAR, radar, ultrasound, or other sensors. The number of input nodes202, hidden layers 204-208, and output notes 210 is illustrative only.For example, larger networks may include an input node 202 for eachpixel of an image, and thus may have hundreds, thousands, or othernumber of input nodes.

According to one embodiment, a deep neural network 200 of FIG. 2 may beused to classify the content(s) of an image into four different classes:a first class, a second class, a third class, and a fourth class.According to the present disclosure, a similar or differently sizedneural network may be able to output a value indicating whether aspecific type of object is present within the image (or of sub-region ofthe image that was fed into the network 200). For example, the firstclass may correspond to whether there is a vehicle present, the secondclass may correspond to whether there is a bicycle present, the thirdclass may correspond to whether there is a pedestrian present, and thefourth class may correspond to whether there is a curb or barrierpresent. An output corresponding to a class may be high (e.g., 0.5 orgreater) when an object in the corresponding class is detected and low(e.g., less than 0.5) when an object of the class is not detected. Thisis illustrative only as a neural network to classify objects in an imageand may include inputs to accommodate hundreds or thousands of pixelsand may need to detect a larger number of different types of objects.Thus, a neural network to detect or classify objects in a camera imageor other sensor frame may require hundreds or thousands of nodes at aninput layer and/or more than (or less than) four output nodes.

For example, feeding a portion of a raw sensor frame (e.g., an image,LIDAR frame, radar frame, or the like captured by the captured by sensorof a vehicle control system 100) into the network 200 may indicate thepresence of a pedestrian in that portion. Therefore, the neural network100 may enable a computing system to automatically infer that apedestrian is present at a specific location within an image or sensorframe and with respect to the vehicle. Similar techniques or principlesmay be used to infer information about or detecting vehicles, trafficsigns, bicycles, barriers, and or the like.

A neural network (with or without recurrent connections) may also beused to identify or detect features within a sensor frame or withinsub-regions of a sensor frame.

The neural network 200 also includes a plurality of recurrentconnections between the output nodes 210 and the input nodes 202. Valuesat the output nodes 210 may be fed back through delays 212 to one ormore input nodes. The delays 212 may delay/save the output values forinput during a later sensor frame. For example, a subset of the inputnodes 202 may receive the output from a previous sensor frame (such asan image frame) while the remaining input nodes 202 may receive pixel orpoint values for a current sensor frame. Thus, the output of theprevious frame can affect whether a specific object or feature isdetected again. For example, if a pedestrian is detected in the image,the output indicating the presence of the pedestrian may be fed into aninput node 202 so that the network is more likely to detect thepedestrian in the subsequent frame. This can be useful in video wherethere a series of images are captured and a vehicle needs to detect andavoid obstacles. Additionally, any sensor that provides a series ofsensor frames (e.g., such as LIDAR or RADAR) can also benefit from therecurrent connection.

Although the neural network 200 is shown with the recurrent connectionbetween the output nodes 210 and the input nodes 202, the recurrentconnection may occur between any node or layer in different embodiments.For example, a recurrent connection may feed the values of the outputnodes 210 into nodes in a hidden layer (e.g., 204, 206, and 208) or asinput into the output nodes 210. The recurrent connections may allow thedetection of objects or features from a previous sensor frame to affectthe detection of objects or features for a later sensor frame.

In order for a deep neural network to be able to distinguish between anydesired classes, the neural network needs to be trained based onexamples. Once the images with labels (training data) are acquired, thenetwork may be trained. One example algorithm for training includes theback propagation-algorithm that may use labeled sensor frames to train aneural network. The training may not only train the neural network 200on how to detect objects or features based on sensor data, but alsobased on outputs or information determined from a previous set ofpixel/frame data. Once trained, the neural network 200 may be ready foruse in an operating environment.

FIG. 3 illustrates an image 300 of a perspective view that may becaptured by a camera of a vehicle in a driving environment. For example,the image 300 illustrates a scene of a road in front of a vehicle thatmay be captured while a vehicle is traveling down the road. The image300 includes a plurality of objects of interest on or near the roadway.In one embodiment, the image 300 is too large to be processed at fullresolution by an available neural network. Thus, the image may beprocessed one sub-region at a time. For example, the window 302represents a portion of the image 302 that may be fed to a neuralnetwork for object or feature detection. The window 302 may be slid todifferent locations to effectively process the whole image 302. Forexample, the window 302 may start in a corner and then be subsequentlymoved from point to point to detect features.

In one embodiment, different sizes of sliding windows may be used tocapture features or objects at different resolutions. For example,features or objects closer to a camera may be more accurately detectedusing a larger window while features or objects further away from thecamera may be more accurately detected using a smaller window. Largerwindows may be reduced in resolution to match the number of input nodesof a neural network. For example, the image 300 may be down sampled toprocess the full image 300 or a larger portion or different scale window302 of the image 300.

In one embodiment, outputs of a neural network for each location of thewindow 302 may be fed forward for the same or nearby location of thewindow 302 on a subsequent image. For example, if a pedestrian isdetected by a neural network at one location in a first image, anindication that a pedestrian was detected at that location may be fedforward during pedestrian detection at that location for a second, laterimage using the neural network. Similarly, features detected at aspecific location in an image or other sensor frame may be fed forward.Thus, objects or features in a series of images may be consistentlydetected and/or tracked at the neural network or model layer.

In one embodiment, after or as a result of processing using a slidingwindow, a feature map may be generated that indicates what features orobjects were located at which locations. The feature map may includeindications of low level image (or other sensor frame) features that maybe of interested in detecting objects or classifying objects. Forexample, the features may include boundaries, curves, corners, or otherfeatures that may be indicative of the type of object at a location(such as a vehicle, face of a pedestrian, or the like). The feature mapsmay then be used for object detection or classification. For example, afeature map may be generated and then the feature map and/or the regionof the image may be processed to identify a type of object and/or tracka location of the object between frames of sensor data. The feature mapmay indicate where in the image 300 certain types of features aredetected. In one embodiment, a plurality of different recurrent neuralnetworks may be used to generate each feature map. For example, afeature map for pedestrian detection may be generated using a neuralnetwork trained for pedestrian detection while a feature map for vehicledetection may be generated using a neural network trained for vehicledetection. Thus, a plurality of different feature maps may be generatedfor the single image 300 shown in FIG. 3. As discussed previously, thedetected features may be fed forward between frames for the samesub-regions to improve feature tracking and/or object detection.

Although FIG. 3 shows an image, similar processing can be performed onany type of sensor data or frame of data. For example, a depth map maybe similarly processed using windows, neural networks, and the like todetect features or objects. In one embodiment, frames of different typesof sensor data may each be processed to generate one or more featuremaps that can then be combined into a concatenated feature map. With theconcatenated feature map, the features may include all features detectedby any of the available sensors or data sources. Thus, even if nofeatures are detected based on data from one of the sensors, thefeatures detected based on data from the remaining sensors may stillprovide enough information for accurate and reliable feature or objectdetection. For example, vehicles or objects may still be detected in thedark or in sun glare situations based on the features from LIDAR, radar,or other sensor sources. Additionally, the recurrent connections betweenframes may allow for detection of objects or features in even very poorconditions if a previous frame found the objects or features.

FIG. 4 is a schematic block diagram illustrating incorporation oftemporal information between frames of sensor data during objectdetection. A plurality of processing stages including a first stage 402,second stage 404, and third stage 406 for processing of differentimages, including Image 0, Image 1, and Image 2 are shown. Each stage402, 404, 406 may correspond to a different time period for processing adifferent set of sensor data. For example, the stages may correspond toreal-time processing during acquisition of sensor data. The first stage402 shows the input of Image 0 for the generation of one or more featuremaps 408. The feature maps 408 may be generated using one or more neuralnetworks. For each sub-region 410 (such as a location of the window 302of FIG. 3), an object prediction is generated. Both the feature mapgeneration and the object prediction may be performed using one or moreneural networks.

The object predictions may indicate an object type, and/or an objectlocation. For example, a ‘0’ value for the object prediction mayindicate that there is no object, a ‘1’ may indicate that the object isa car, a ‘2’ may indicate that the object is a pedestrian, and so forth.A location value may also be provided that indicates where in thesub-region 410 the object is located. For example, a second number maybe included in the state that indicates a location in the center, right,top, or bottom of the sub-region 410. Recurrent neural network (RNN)state 0-0 is the resulting prediction for object 0 at the sub-region410, RNN state 0-1 is the resulting prediction for object 1 at thesub-region 410, and RNN state 0-2 is the resulting prediction for object2 at the sub-region 410. Thus, a plurality of objects and/or objectpredictions may be detected or generated for each sub-region 410.

The state information, including RNN state 0-0, RNN state 0-1, and RNNstate 0-2 from stage 402 is fed forward using a recurrent connection 420for use during processing of the next image, Image 1 during stage 404.For example, the object predictions and associated values may be fedinto a neural network along the recurrent connection 420 as input to oneor more nodes of the same one or more neural networks during processingof Image 1 and/or its feature maps 412. During stage 404, objectpredictions are generated based not only on Image 1 and the feature maps412, but also based on RNN state 0-0, RNN state 0-1, and RNN state 0-2.The result of prediction results in RNN state 1-0, RNN state 1-1, andRNN state 1-2 for the sub-region 414. The recurrent connection 420 mayfeed forward state information for the same sub-region 410. Thus, onlystate information for the same sub-region from the previous image may beused to determine an object prediction or feature detection for acurrent image. In one embodiment, detected features in the feature maps408 are also fed forward along the recurrent connection 420. Thus,recurrent neural networks may be used to generate the feature maps aswell as the object predictions.

During stage 406, object predictions are generated based not only onImage 2 and the feature maps 416, but also based on the stateinformation including RNN state 1-0, RNN state 1-1, and RNN state 1-2,which is fed forward using a recurrent connection 422 for use duringprocessing of Image 2 for sub-region 418. Object predictions for RNNstate 2-0, RNN state 2-1, and RNN state 2-2 are determined based onImage 2 as well as the state information including RNN state 1-0, RNNstate 1-1, and RNN state 1-2 from Image 1. Additionally, the featuremaps 416 may be generated based on the feature maps (or locations ofdetected features) for the previous, second stage 404.

In one embodiment, the processing that occurs in each stage 402, 404,406 occurs in real-time on a stream of incoming sensor data. Forexample, when processing a video, each frame of the video may beprocessed and the corresponding object predictions, feature detections,and/or feature maps may be saved/input into the models or neuralnetworks when the next frame of the video is received. Thus, therecurrent connections 420, 422 allow for object predictions to becarried over from an earlier frame to a later frame. Thus, temporalinformation may be incorporated at the model or neural network level,which allows a neural network to be trained to and process not onlyinformation for a present sensor frame but also previous sensor frames.This is different from embodiments where features are extracted anew foreach frame and then discarded. In one embodiment, a single neuralnetwork, or set of neural networks is used during each stage such thatthe recurrent connections 420, 422 simply feedback outputs from previousframes as input into a current frame.

FIG. 5 is a schematic flow chart diagram illustrating a method 500 forobject detection. The method 500 may be performed by a detectioncomponent or vehicle control system such as the detection component 104or vehicle control system 100 of FIG. 1.

The method 500 begins and a detection component 104 determines at 502,using one or more neural networks, an output for a first sensor frameindicating a presence of an object or feature. For example, thedetection component 104 may determine at 502 any of the objectprediction or states (such as RNN state 0-0, RNN state 0-1, RNN state0-2, RNN state 1-0, RNN state 1-1, or RNN state 1-2) of FIG. 4. Thedetection component 102 may determine at 502 the states based on data ina sensor frame in a series of sensor frames. A sensor component (whichmay include a radar system 106, LIDAR system 108, camera system 110, orother sensor) may capture or obtain sensor frames that include imagedata, LIDAR data, radar data, or infrared image data. A detectioncomponent 104 feeds at 504 the output (which may include an indicationof detected features or objects) for the first sensor frame forward asan input for processing a second sensor frame. For example, thedetection component 104 may include or use a recurrent connection in aneural network. The detection component 104 determines at 506 an outputfor the second sensor frame indicating a presence of an object orfeature based on the output for the first sensor frame. For example, thedetection component 104 may determine any of the object prediction orstates (such as RNN state 1-0, RNN state 1-1, RNN state 1-2, RNN state2-0, RNN state 2-1, or RNN state 2-2) of FIG. 4 based on the states or aprevious stage.

The method 500 may include providing output or predictions to anothersystem for decision making. For example, the automated driving/assistantsystem 102 of FIG. 1 may determine a driving maneuver based on adetected object or feature. Example maneuvers include crash avoidancemaneuvers or other driving maneuvers to safely drive the vehicle. Themethod 500 may also include training the one or more neural networks togenerate output based on data for a later image frame using an outputfrom an earlier frame. The method 500 may allow for more efficient andaccurate object detection and tracking in a series of sensor frames,such as within video. The improved object detection and tracking mayimprove driving and passenger safety and accuracy.

FIG. 6 is a schematic block diagram illustrating incorporation oftemporal information from multiple types of sensor data and between setsof frames of sensor data during object detection. A plurality ofprocessing stages including a first stage 602, second stage 604, andthird stage 606 for processing of different sets of sensor frames areshown. The sensor frames include images (Image 0, Image 1, and Image 2)as well as depth maps (Depth 0, Depth 1, and Depth 2) which areprocessed during their respective stages, although other types of sensordata or frames may be used. Each stage 602, 604, 606 may correspond to adifferent time period for processing a different set of sensor data. Forexample, the stages may correspond to real-time processing duringacquisition of sensor data of the most recently captured sensor data.

The first stage 602 shows the input of Image 0 and Depth 0 which areeach processed to generate one or more feature maps. For example, Image0 may be processed with one or more neural networks to generate one ormore different feature maps that reflect where certain types of featureswere detected. Similarly, more than one feature map may be generatedbased on Depth 0. The feature maps are input into a convolutionalrecurrent neural network or other model which uses multiscaleconvolutions to generate concatenated feature maps 608. The concatenatedfeature maps 608 may include all the features of the respective sensorfeature maps. For example, a concatenated feature map may includeindications of features detected by both an image feature map and adepth feature map.

The concatenated feature maps may be processed for object detection. Foreach sub-region 614 (such as a location of the window 302 of FIG. 3), anobject prediction is generated. The sensor feature map generation,concatenated feature map generation, and the object prediction may beperformed using one or more neural networks. The object predictions mayinclude Obj 0 prediction and an Obj 1 prediction, which were generatedbased on the sub-region 614 of the concatenated feature map 608. Theobject prediction may include an object type or classification as wellas location.

Similar to the embodiment of FIG. 4, recurrent connections 620, 622 feedforward information between processing stages. For example, featuremaps, detected features, object predictions, or the like may be bedforward to a recurrent convolutional neural network for use duringprocessing of a subsequent set of images. Thus, temporal information maybe taken into account during object or feature detection. The feature orobjects detected for a previous time period (e.g., the time periodcorresponding to a previous set of sensor frames) may be fed forward andaffect whether those same objects or feature are detected for a laterset of sensor frames. During stage 604 and stage 606, similar generationof concatenated feature maps 610 and 612 and object predictions forsub-regions 616 and 618 can be performed and fed forward using recurrentconnections 622 and 624.

FIG. 7 a schematic flow chart diagram illustrating a method 700 forobject detection. The method 700 may be performed by a detectioncomponent or vehicle control system such as the detection component 104or vehicle control system 100 of FIG. 1.

The method 700 begins and one or more sensor components obtain at 702 afirst stream of sensor data and a second stream of sensor data. Each ofthe first stream and second stream include a plurality of sensor frames.For example, a sensor component may include one or more of the sensors106, 108, 110, 114, or other sensor. A detection component 104 generatesat 704 a concatenated feature map based on a sensor frame of a firsttype and a sensor frame of a second type. The sensor frame may be fromor based on the first stream and the sensor frame of the second type maybe from or based on the second stream. The detection component 104detects at 706 one or more objects based on the concatenated featuremap. In one embodiment, one or more of generating at 704 and detectingat 706 comprises generating or detecting using a neural network with arecurrent connection that feeds information about features or objectsfrom previous frames.

Referring now to FIG. 8, a block diagram of an example computing device800 is illustrated. Computing device 800 may be used to perform variousprocedures, such as those discussed herein. In one embodiment, thecomputing device 800 can function as a detection component 104,automated driving/assistance system 102, vehicle control system 100, orthe like. Computing device 800 can perform various monitoring functionsas discussed herein, and can execute one or more application programs,such as the application programs or functionality described herein.Computing device 800 can be any of a wide variety of computing devices,such as a desktop computer, in-dash computer, vehicle control system, anotebook computer, a server computer, a handheld computer, tabletcomputer and the like.

Computing device 800 includes one or more processor(s) 802, one or morememory device(s) 804, one or more interface(s) 806, one or more massstorage device(s) 808, one or more Input/Output (I/O) device(s) 810, anda display device 830 all of which are coupled to a bus 812. Processor(s)802 include one or more processors or controllers that executeinstructions stored in memory device(s) 804 and/or mass storagedevice(s) 808. Processor(s) 802 may also include various types ofcomputer-readable media, such as cache memory.

Memory device(s) 804 include various computer-readable media, such asvolatile memory (e.g., random access memory (RAM) 814) and/ornonvolatile memory (e.g., read-only memory (ROM) 816). Memory device(s)804 may also include rewritable ROM, such as Flash memory.

Mass storage device(s) 808 include various computer readable media, suchas magnetic tapes, magnetic disks, optical disks, solid-state memory(e.g., Flash memory), and so forth. As shown in FIG. 8, a particularmass storage device is a hard disk drive 824. Various drives may also beincluded in mass storage device(s) 808 to enable reading from and/orwriting to the various computer readable media. Mass storage device(s)808 include removable media 826 and/or non-removable media.

I/O device(s) 810 include various devices that allow data and/or otherinformation to be input to or retrieved from computing device 800.Example I/O device(s) 810 include cursor control devices, keyboards,keypads, microphones, monitors or other display devices, speakers,printers, network interface cards, modems, and the like.

Display device 830 includes any type of device capable of displayinginformation to one or more users of computing device 800. Examples ofdisplay device 830 include a monitor, display terminal, video projectiondevice, and the like.

Interface(s) 806 include various interfaces that allow computing device800 to interact with other systems, devices, or computing environments.Example interface(s) 806 may include any number of different networkinterfaces 820, such as interfaces to local area networks (LANs), widearea networks (WANs), wireless networks, and the Internet. Otherinterface(s) include user interface 818 and peripheral device interface822. The interface(s) 806 may also include one or more user interfaceelements 818. The interface(s) 806 may also include one or moreperipheral interfaces such as interfaces for printers, pointing devices(mice, track pad, or any suitable user interface now known to those ofordinary skill in the field, or later discovered), keyboards, and thelike.

Bus 812 allows processor(s) 802, memory device(s) 804, interface(s) 806,mass storage device(s) 808, and I/O device(s) 810 to communicate withone another, as well as other devices or components coupled to bus 812.Bus 812 represents one or more of several types of bus structures, suchas a system bus, PCI bus, IEEE bus, USB bus, and so forth.

For purposes of illustration, programs and other executable programcomponents are shown herein as discrete blocks, although it isunderstood that such programs and components may reside at various timesin different storage components of computing device 800, and areexecuted by processor(s) 802. Alternatively, the systems and proceduresdescribed herein can be implemented in hardware, or a combination ofhardware, software, and/or firmware. For example, one or moreapplication specific integrated circuits (ASICs) can be programmed tocarry out one or more of the systems and procedures described herein.

EXAMPLES

The following examples pertain to further embodiments.

Example 1 is a method for detecting objects or features in sensor data.The method includes generating a concatenated feature map based on asensor frame of a first type and a sensor frame of a second type. Themethod includes detecting one or more objects based on the concatenatedfeature map. In the method, one or more of generating and detectingincludes generating or detecting using a neural network with a recurrentconnection that feeds information about features or objects fromprevious frames.

In Example 2, the method of Example 1 further includes generating afirst feature map based on the sensor frame of the first type andgenerating a second feature map based on the sensor frame of the secondtype. Generating the concatenated feature map includes generating basedon the high-level features in the first feature map or the secondfeature map.

In Example 3, generating the concatenated feature map as in Example 2includes generating a fused feature map that includes the features fromboth the first feature map and the second feature map.

In Example 4, the sensor frame of the first type as in any of Examples1-3 includes an image and the sensor frame of the second type includes adepth map.

In Example 5, the recurrent connection of the neural network as in anyof Examples 1-4 feeds forward one or more of a feature in a previousconcatenated feature map, an object detected in a previous frame or timeperiod, and a feature in a previous sensor frame.

In Example 6, the sensor frame of the first type as in any of Examples1-5 includes a first sensor frame of the first type, the sensor frame ofthe second type includes a first sensor frame of the second type, theconcatenated feature map includes a first concatenated feature map, andthe one or more objects include first one or more objects. The methodfurther includes generating a second concatenated feature map based on asecond sensor frame of the first type and a second sensor frame of thesecond type. The method further includes detecting second one or moreobjects based on the second concatenated feature map. The method furtherincludes feeding forward one or more of a feature of the secondconcatenated feature map or the second one or more objects using therecurrent connection of the neural network for generating the firstconcatenated feature map or detecting the first one or more objects.

In Example 7, the neural network as in any Examples 16 includes an inputlayer, one or more hidden layers, and a classification layer. Therecurrent connection feeds an output of the classification layer fromprevious frames into one or more of the input layer or a hidden layer ofthe one or more hidden layers during generating the concatenated featuremap or detecting the one or more objects.

In Example 8, the method as in any of Examples 1-7 includes determininga feature or detecting an object for a plurality of sub-regions, whereina feature or object for the plurality of sub-regions is fed forward asinput for a corresponding sub-region for a later time period.

In Example 9, determining a feature or detecting an object for aplurality of sub-regions as in Example 8 includes determining featuresor detecting objects for different sized sub-regions to detect differentsized features or objects.

In Example 10, the recurrent connection as in any of Examples 1-9 feedsforward information including one or more of an indication of a type ofobject or feature detected or an indication of a location of the objector feature.

In Example 11, the method as in any of Examples 1-10 further includesdetermining a driving maneuver based on the detected one or more objectsor features of the concatenated feature map.

In Example 12, the method as in any of Examples 1-11 further includestraining the neural network to detect objects or features using therecurrent connection.

Example 13 is computer readable storage media storing instructions that,when executed by one or more processors, cause the one or moreprocessors to implement a method as in any of Examples 1-12.

Example 14 is a system or device that includes means for implementing amethod or realizing a system or apparatus in any of Examples 1-13.

In the above disclosure, reference has been made to the accompanyingdrawings, which form a part hereof, and in which is shown by way ofillustration specific implementations in which the disclosure may bepracticed. It is understood that other implementations may be utilizedand structural changes may be made without departing from the scope ofthe present disclosure. References in the specification to “oneembodiment,” “an embodiment,” “an example embodiment,” etc., indicatethat the embodiment described may include a particular feature,structure, or characteristic, but every embodiment may not necessarilyinclude the particular feature, structure, or characteristic. Moreover,such phrases are not necessarily referring to the same embodiment.Further, when a particular feature, structure, or characteristic isdescribed in connection with an embodiment, it is submitted that it iswithin the knowledge of one skilled in the art to affect such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described.

Implementations of the systems, devices, and methods disclosed hereinmay comprise or utilize a special purpose or general-purpose computerincluding computer hardware, such as, for example, one or moreprocessors and system memory, as discussed herein. Implementationswithin the scope of the present disclosure may also include physical andother computer-readable media for carrying or storingcomputer-executable instructions and/or data structures. Suchcomputer-readable media can be any available media that can be accessedby a general purpose or special purpose computer system.Computer-readable media that store computer-executable instructions arecomputer storage media (devices). Computer-readable media that carrycomputer-executable instructions are transmission media. Thus, by way ofexample, and not limitation, implementations of the disclosure cancomprise at least two distinctly different kinds of computer-readablemedia: computer storage media (devices) and transmission media.

Computer storage media (devices) includes RAM, ROM, EEPROM, CD-ROM,solid state drives (“SSDs”) (e.g., based on RAM), Flash memory,phase-change memory (“PCM”), other types of memory, other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium, which can be used to store desired program code means inthe form of computer-executable instructions or data structures andwhich can be accessed by a general purpose or special purpose computer.

An implementation of the devices, systems, and methods disclosed hereinmay communicate over a computer network. A “network” is defined as oneor more data links that enable the transport of electronic data betweencomputer systems and/or modules and/or other electronic devices. Wheninformation is transferred or provided over a network or anothercommunications connection (either hardwired, wireless, or a combinationof hardwired or wireless) to a computer, the computer properly views theconnection as a transmission medium. Transmissions media can include anetwork and/or data links, which can be used to carry desired programcode means in the form of computer-executable instructions or datastructures and which can be accessed by a general purpose or specialpurpose computer. Combinations of the above should also be includedwithin the scope of computer-readable media.

Computer-executable instructions comprise, for example, instructions anddata which, when executed at a processor, cause a general purposecomputer, special purpose computer, or special purpose processing deviceto perform a certain function or group of functions. The computerexecutable instructions may be, for example, binaries, intermediateformat instructions such as assembly language, or even source code.Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the described features or acts described above.Rather, the described features and acts are disclosed as example formsof implementing the claims.

Those skilled in the art will appreciate that the disclosure may bepracticed in network computing environments with many types of computersystem configurations, including, an in-dash vehicle computer, personalcomputers, desktop computers, laptop computers, message processors,hand-held devices, multi-processor systems, microprocessor-based orprogrammable consumer electronics, network PCs, minicomputers, mainframecomputers, mobile telephones, PDAs, tablets, pagers, routers, switches,various storage devices, and the like. The disclosure may also bepracticed in distributed system environments where local and remotecomputer systems, which are linked (either by hardwired data links,wireless data links, or by a combination of hardwired and wireless datalinks) through a network, both perform tasks. In a distributed systemenvironment, program modules may be located in both local and remotememory storage devices.

Further, where appropriate, functions described herein can be performedin one or more of: hardware, software, firmware, digital components, oranalog components. For example, one or more application specificintegrated circuits (ASICs) can be programmed to carry out one or moreof the systems and procedures described herein. Certain terms are usedthroughout the description and claims to refer to particular systemcomponents. The terms “modules” and “components” are used in the namesof certain components to reflect their implementation independence insoftware, hardware, circuitry, sensors, or the like. As one skilled inthe art will appreciate, components may be referred to by differentnames. This document does not intend to distinguish between componentsthat differ in name, but not function.

It should be noted that the sensor embodiments discussed above maycomprise computer hardware, software, firmware, or any combinationthereof to perform at least a portion of their functions. For example, asensor may include computer code configured to be executed in one ormore processors, and may include hardware logic/electrical circuitrycontrolled by the computer code. These example devices are providedherein purposes of illustration, and are not intended to be limiting.Embodiments of the present disclosure may be implemented in furthertypes of devices, as would be known to persons skilled in the relevantart(s).

At least some embodiments of the disclosure have been directed tocomputer program products comprising such logic (e.g., in the form ofsoftware) stored on any computer useable medium. Such software, whenexecuted in one or more data processing devices, causes a device tooperate as described herein.

While various embodiments of the present disclosure have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation. It will be apparent to persons skilledin the relevant art that various changes in form and detail can be madetherein without departing from the spirit and scope of the disclosure.Thus, the breadth and scope of the present disclosure should not belimited by any of the above-described exemplary embodiments, but shouldbe defined only in accordance with the following claims and theirequivalents. The foregoing description has been presented for thepurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure to the precise form disclosed.Many modifications and variations are possible in light of the aboveteaching. Further, it should be noted that any or all of theaforementioned alternate implementations may be used in any combinationdesired to form additional hybrid implementations of the disclosure.

Further, although specific implementations of the disclosure have beendescribed and illustrated, the disclosure is not to be limited to thespecific forms or arrangements of parts so described and illustrated.The scope of the disclosure is to be defined by the claims appendedhereto, any future claims submitted here and in different applications,and their equivalents.

1. A method comprising: generating a concatenated feature map based on asensor frame of a first type and a sensor frame of a second type; anddetecting one or more objects based on the concatenated feature map;wherein one or more of generating and detecting comprises generating ordetecting using a neural network with a recurrent connection that feedsinformation about features or objects from previous frames.
 2. Themethod of claim 1, further comprising generating a first feature mapbased on the sensor frame of the first type and generating a secondfeature map based on the sensor frame of the second type, whereingenerating the concatenated feature map comprises generating based onthe high-level features in the first feature map or the second featuremap.
 3. The method of claim 2, wherein generating the concatenatedfeature map comprises generating a fused feature map that includes thefeatures from both the first feature map and the second feature map. 4.The method of claim 1, wherein the sensor frame of the first typecomprise an image and wherein the sensor frame of the second typecomprises a depth map.
 5. The method of claim 1, wherein the neuralnetwork feeds forward one or more of: a feature in a previousconcatenated feature map; an object detected in a previous frame or timeperiod; and a feature in a previous sensor frame.
 6. The method of claim1, wherein the sensor frame of the first type comprises a first sensorframe of the first type, the sensor frame of the second type comprises afirst sensor frame of the second type, the concatenated feature mapcomprises a first concatenated feature map, and the one or more objectscomprise first one or more objects, wherein the method furthercomprises: generating a second concatenated feature map based on asecond sensor frame of the first type and a second sensor frame of thesecond type; detecting second one or more objects based on the secondconcatenated feature map; and feeding forward one or more of a featureof the second concatenated feature map or the second one or more objectsusing the recurrent connection of the neural network for generating thefirst concatenated feature map or detecting the first one or moreobjects.
 7. The method of claim 1, wherein the neural networks comprisesan input layer, one or more hidden layers, and a classification layer,wherein the recurrent connection feeds an output of the classificationlayer from the previous frames into one or more of the input layer or ahidden layer of the one or more hidden layers during generating theconcatenated feature map or detecting the one or more objects.
 8. Asystem comprising: one or more sensor components configured to obtain afirst stream of sensor data and a second stream of sensor data, whereineach of the first stream and second stream comprise a plurality ofsensor frames; a detection component configured to: generate aconcatenated feature map based on a sensor frame of a first type and asensor frame of a second type; and detect one or more objects based onthe concatenated feature map; wherein one or more of generating anddetecting comprises generating or detecting using a neural network witha recurrent connection that feeds information about features or objectsfrom previous frames.
 9. The system of claim 8, wherein the detectioncomponent is further configured to generate a first feature map based onthe sensor frame of the first type and generate a second feature mapbased on the sensor frame of the second type, wherein the detectioncomponent generates the concatenated feature map by generating based onthe high-level features in the first feature map or the second featuremap.
 10. The system of claim 9, wherein the detection component isconfigured to generate the concatenated feature map by generating afused feature map that includes the features from both the first featuremap and the second feature map.
 11. The system of claim 8, wherein thesensor frame of the first type comprise an image and wherein the sensorframe of the second type comprises a depth map.
 12. The system of claim8, wherein the recurrent connection of the neural network feeds forwardone or more of: a feature in a previous concatenated feature map; anobject detected based on previous frames or a previous time period; anda feature in a previous sensor frame.
 13. The system of claim 8, whereinthe sensor frame of the first type comprises a first sensor frame of thefirst type, the sensor frame of the second type comprises a first sensorframe of the second type, the concatenated feature map comprises a firstconcatenated feature map, and the one or more objects comprise first oneor more objects, wherein the detection component is further configuredto: generate a second concatenated feature map based on a second sensorframe of the first type and a second sensor frame of the second type;detect second one or more objects based on the second concatenatedfeature map; and feed forward one or more of a feature of the secondconcatenated feature map or the second one or more objects using therecurrent connection of the neural network for generating the firstconcatenated feature map or detecting the first one or more objects. 14.The system of claim 8, wherein the neural networks comprises an inputlayer, one or more hidden layers, and a classification layer, whereinthe recurrent connection feeds an output of the classification layerfrom the previous frames into one or more of the input layer or a hiddenlayer of the one or more hidden layers during generating theconcatenated feature map or detecting the one or more objects. 15.Computer readable storage media storing instructions that, when executedby one or more processors, cause the one or more processors to: obtain afirst stream of sensor data and a second stream of sensor data, whereineach of the first stream and second stream comprise a plurality ofsensor frames; generate a concatenated feature map based on a sensorframe of a first type and a sensor frame of a second type; and detectone or more objects based on the concatenated feature map; wherein oneor more of generating and detecting comprises generating or detectingusing a neural network with a recurrent connection that feedsinformation about features or objects from previous frames.
 16. Thecomputer readable storage media of claim 15, wherein the instructionsfurther cause the one or more processors to generate a first feature mapbased on the sensor frame of the first type and generate a secondfeature map based on the sensor frame of the second type, wherein theinstructions cause the one or more processors to generate theconcatenated feature map by generating based on the high-level featuresin the first feature map or the second feature map.
 17. The computerreadable storage media of claim 16, wherein the instructions cause theone or more processors to generate the concatenated feature map bygenerating a fused feature map that includes the features from both thefirst feature map and the second feature map.
 18. The computer readablestorage media of claim 15, wherein the sensor frame of the first typecomprise an image and wherein the sensor frame of the second typecomprises a depth map.
 19. The computer readable storage media of claim15, wherein the instructions further cause the one or more processors tofeeds forward one or more of the following using the recurrentconnection of the neural network: a feature in a previous concatenatedfeature map; an object detected based on previous frames or a previoustime period; and a feature in a previous sensor frame.
 20. The computerreadable storage media of claim 15, wherein the sensor frame of thefirst type comprises a first sensor frame of the first type, the sensorframe of the second type comprises a first sensor frame of the secondtype, the concatenated feature map comprises a first concatenatedfeature map, and the one or more objects comprise first one or moreobjects, wherein the instructions further cause the one or moreprocessors to: generate a second concatenated feature map based on asecond sensor frame of the first type and a second sensor frame of thesecond type; detect second one or more objects based on the secondconcatenated feature map; and feed forward one or more of a feature ofthe second concatenated feature map or the second one or more objectsusing the recurrent connection of the neural network for generating thefirst concatenated feature map or detecting the first one or moreobjects.